The present disclosure describes subject matter that relates to closed loop systems, with particular discussion about embodiments of systems that are configured with a cooling system that utilizes a working fluid to evacuate and cool components.
Systems that generate power include closed loop systems that operate under principles of a Rankine Thermodynamic Cycle. These systems use thermal energy from a thermal source fluid to evaporate a working fluid, e.g., a low temperature boiling organic fluid. This process generates high pressure vapor. In conventional designs, the system directs the vapor to power generating machinery, for example, a turbine or like device, that can operate a generator to generate electric power. The system can also cool and condense the vapor to liquid form.
FIG. 1 illustrates a schematic diagram of an example of a conventional closed loop system 100. This embodiment includes a pump component 102, an evaporator component 104 (that utilizes a source fluid S), a power generating component 106, and a condenser component 108 (that utilizes a cooling medium C). The system 100 also includes a fluid circuit 110, typically a construction of fluid conduits (e.g., pipes, tubes, valves, etc.) that couple the components 102, 104, 106, 108 together. The fluid circuit 110 allows a working fluid F to circulate among the components 102, 104, 106, 108. In the example of FIG. 1, the working fluid F exhibits one or more set of working properties (e.g., a first set 112, a second set 114, a third set 116, and a fourth set 118), each set being configured to identify, for example, a pressure and a temperature of the working fluid F that circulates through the fluid circuit 110. The value of the working properties often correspond to phases (e.g., liquid, vapor, etc.) of the working fluid F. As also shown in FIG. 1, the fluid circuit 110 may include a cooling circuit 120 that directs working fluid F to the power generating component 106. The flow of the working fluid F in the cooling circuit 120 distributes the working fluid F as a cooling fluid with working properties to remove heat from certain components including, for example, elements (e.g., motor(s), electronics, etc.) of a generator.
The temperature of the cooling fluid in the cooling circuit 120 is related to the saturation temperature of the working fluid F at the pressure at which the working fluid F is allowed to expand. In closed loop systems like the system 100 of FIG. 1, the lowest pressure of the working fluid F is at the outlet of the condenser component 108. This pressure is roughly related to ambient temperature, e.g., of the environment surrounding the system 100. Unfortunately, an increase in ambient temperature can cause an increase in both the temperature of the working fluid F at the outlet of the condenser component 108 and the corresponding saturation pressure. This rise in temperature of the working fluid F also increases the temperature of the cooling fluid in the cooling circuit 120, which may in turn render the cooling fluid insufficient to cool elements and critical components to safe operating temperatures. As a result, designers may need to de-rate the system and/or power generating machinery based on the cooling effect alone to reflect a lower output during operations at operating conditions with higher ambient temperatures.